| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.74 |
| Score | 0% | 55% |
If a = -7 and z = 2, what is the value of 7a(a - z)?
| 408 | |
| -128 | |
| -648 | |
| 441 |
To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)
7a(a - z)
7(-7)(-7 - 2)
7(-7)(-9)
(-49)(-9)
441
Which of the following is not required to define the slope-intercept equation for a line?
\({\Delta y \over \Delta x}\) |
|
y-intercept |
|
slope |
|
x-intercept |
A line on the coordinate grid can be defined by a slope-intercept equation: y = mx + b. For a given value of x, the value of y can be determined given the slope (m) and y-intercept (b) of the line. The slope of a line is change in y over change in x, \({\Delta y \over \Delta x}\), and the y-intercept is the y-coordinate where the line crosses the vertical y-axis.
The endpoints of this line segment are at (-2, 3) and (2, -7). What is the slope of this line?
| -1 | |
| 1\(\frac{1}{2}\) | |
| -2\(\frac{1}{2}\) | |
| \(\frac{1}{2}\) |
The slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, 3) and (2, -7) so the slope becomes:
m = \( \frac{\Delta y}{\Delta x} \) = \( \frac{(-7.0) - (3.0)}{(2) - (-2)} \) = \( \frac{-10}{4} \)The formula for the area of a circle is which of the following?
a = π d |
|
a = π r2 |
|
a = π r |
|
a = π d2 |
The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)2 : a = π r2.
Find the value of a:
-7a + y = -7
8a - 8y = 6
| -\(\frac{32}{53}\) | |
| \(\frac{8}{21}\) | |
| 1\(\frac{1}{24}\) | |
| 5\(\frac{1}{3}\) |
You need to find the value of a so solve the first equation in terms of y:
-7a + y = -7
y = -7 + 7a
then substitute the result (-7 - -7a) into the second equation:
8a - 8(-7 + 7a) = 6
8a + (-8 x -7) + (-8 x 7a) = 6
8a + 56 - 56a = 6
8a - 56a = 6 - 56
-48a = -50
a = \( \frac{-50}{-48} \)
a = 1\(\frac{1}{24}\)